Electrically controlled liquid level indicator



Jan. 11, 1938.

c. A. DE GIERS ELECTRICALLY CONTROLLED LIQUID LEVEL INDICATOR Filed May10, 1954 2 Sheets-Sheet l hp l| 0 mi m INVENTOR ATTORNEY" Jan. 11, 1938.

c. A. DE GIERS ELECTRICALLY CONTROLLED LIQUID LEVEL INDICATOR Filed. May10 2 Sheets-Sheet 2 INVENTQR ATTORNEY Patented Jan. 11, 1938 UNITEDSTATES PATENT OFFICE ELECTRICALLY CONTROLLED LIQUID LEVEL 3 Claims.

lhis invention pertains to instruments for indicating the amount ofliquid in a tank.

Ah object of the invention is to improve the type of instrumentdisclosed in my Patent No. 1,945,736. In that apparatus the indicator,in the form of a graduated chart and pointer, is attached directly tothe tank. The present invention contemplates the removal of theindicator to a point remote from the tank. and the operation of theindicator electrically under control of the float in the tank. Thisremote control is effected through the agency of a float actuatedrheostat at the tank and wired to the remote indicator.

Another object is to provide means for operatively connecting anindicator with a plurality of tanks similar to each other, so that thecontents of any selected tank may be instantly determined.

Another object is to operatively connect an indicator to a plurality offloat-controlled rheostats. placed at different elevations in a tank toodeep for a single float, so as to indicate the tank contents at anyliquid level.

Another object is to provide improved means for sealing the rheostatchamber from the tank contents, thereby removing the fire hazard, incase the tank contents are inflammable.

Further and other objects and advantages will be apparent from thespecification and claims, and from the accompanying drawings whichiilustrate what is now considered the preferred embodiment of theinvention.

Fig. l is an elevation, partlyin section, of a rheostat, its housing andits actuating mechanism, installed on a tank.

Fig. 2 is an enlarged view on line 2-Z of Fig. 1.

Fig. 3 is an enlarged view on line 3--3 of Fig. 1.,

Fig. 4 is a diagrammatic view of a series of instruments placed oneabove the other in a deep tank, and indicating the contents on a singleindicator.

Fig. 5 is a wiring diagram of the arrangement of Fig. 4.

Fig. 6 is a diagrammatic representation of four similar tanks, and asingle indicator adapted to indicate the liquid level in any selectedtank.

Referring to Figs. 1, 2 and 3, i0 designates a float, pivotally mountedon the end of float arm l2, and adapted to rest on liquid in a tank. ArmI2 is fulcrumed at H on the end of a tubular support 16 projecting fromthe body of the rheostat chamber l8, which is mounted on a ring 20welded to tank 22 and secured thereto by screws 23. Packing 24 makes atight Joint between body iiiand ring 20. The short end of arm I!isconnected at 26 to a link 28, which at its other end is connected at30 to one end of a curved arm 33, the other end of which is rigidlyattached to the lower end of stud 32, which through 5 theinstrumentality of yoke 34, (rigid with the upper end of stud 32) ispivoted for rocking movement on trunnions 36. 36, substantially inalignment with pivot 30. Sealed to the upper end of stud 32. and hangingdownwardly around the stud and within yoke 34, is a flexible sleeve inthe form of sylphon" 38. The lower open end of the sylphon is sealed tothe cup-shaped plug, 40, which supports trunnions 36 and is tightlythreaded into the lower end of a hollow boss 2, 18 forming an integralextension of housing i8 and projecting through ring 20 into the tank.Also secured to the top of stud 32, by screw 44, is an upwardlyextending arm 46 forming, in effect,

an extension of stud 32, the rocking of which 20 around trunnions 36serves to actuate the rheo stat, as will appear. I

It will be understood from the above that sylphon 38 permits the rockingof stud 32 and its arm 45 about trunnions 36 under control of float 25I0, while hermetically sealing the interior of the housing from thecontents of the tank. It should also be understood that, although thedevice is illustrated in the top of a tank, it is just as well adaptedfor installation in the bottom of the tank or on the side of the tank,either below or above the liquid. This feature is very important in suchjobs as an airplane installation, where the device must be placed on anyavailable part of the tank.

The upper end of arm 6 is connected by link 48 to one end of ahorizontal lever 50 fulcrumed at 52. The other end of lever 50 isconnected by link 54 to a curved arm 56 integral with toothed sector 58supported on a spindle rotatably mounted in upper and lower plates 62and 64 which, with studs 68 and 68, comprise a movement-supporting frameheld in position by screw 10 passing through slot 12 in plate 84,thereby providing a zero adjustment for the instrument.

Sector 58 engages pinion 14, on shaft 16 rotatably supported in frame62-44, so that shaft 16 rotates when arm 56 is rocked by link 54. Thecustomary spring 18 prevents back lash between pinion and sector teeth.Slot 80 in arm 56 provides an adjustable point of connection betweenlink 54 and arm 56 to control the angular rotation of shaft 16 withrelation to the angular motion of float arm l2. In other words, slot I2provides a zero adjustment, and alot I! a capacity adjustment.

Fast on-the upper end of shaft I! is an arm I! having at its outer end ashoe II in contact with the coils of resistance wire .0 wound on aninsulating strip II and supported in the circular insulating cup 00 toform a rheostat under control of float ll. an electric circuit beingprovided through wire 02, plate '2, shaft 18, arm l2, shoe I4,resistance wire I, terminal N and wire I. Wires l2 and It terminate atbinding posts OI and ill on insulating block III within housing ll, andfrom posts 88 and I cables I and I" pass out of the housing through oneof the openings I", H0 or H2, provided for the purpose. whichever ismost convenient. The unused openings are plugged. and the used one isprovided with a sealing device such as HI, and. under certainconditions. a conduit H6. so that there is no possibility of liquid orgas entering the rheos'fht housing. A cover plate ill secured to the topof the housing by screws HI, seals the housing on the side away from thetank.

Wires ill and I" lead to an indicator ill having a pointer Ill movingunder control oi the rheostat over a graduated chart I20. Current issupplied from a source I, and the amount of current flowing through theindicator (and therefore the position of hand i II) is controlled by theposition of arm II, controlled by the float, the position of the floatbeing in turn controlled by the level of liquid in the tank. Thereforethe indicator, with its appropriately graduated chart, gives anindication oi the amount of liquid in the tank.

Pig. 6 shows how a single indicator I24 may be used to indicate thecontents of any selected tank, A, B. C or D, the tanks being of similarshape and dimensions, and each being provided with a float I 28 andrheostat I28 of the type described above. By moving switch Ill intocontact with one of the four contact buttons A, B, C or D a circuit isestablished through the indicator and the rheostat oi the correspondingtank. to show on the indicator the contents of that tank. Thisarrangement is particularly valuable in an airplane. as it enables thepilot, with only one indicator, to ascertain the contents of varioustanks scattered about the machine.

Fig. 4 shows an installation of a plurality of rheostats so arranged ina deep tank as to show the tank contents on a single indicator I".

The rheostats E, P, G and H are supported by brackets (not shown) atdifferent elevations, and their floats E, F, G and H are so arrangedthat as the tank fllls and each float reaches its upper limit of travel(controlled by an adjustable stop ill), the float next above it beginsto move upwardly from its position of rest (controlled by an adjustablestop I"). As the tank is emptied the reverse movement of the floatstakes place.

The rheostats and indicator are interconnected by copper tubes ill, andthe instruments are wired in series, as shown in Pig. 5. As each floatrises it moves its corresponding rheostat arm I! towards "oi!" positionand as the float falls. the arm is moved towards "on" position. Thus inFig. 5 rheostats E, 1" and G are "01!", while H is in an intermediateposition corresponding to the level of the liquid in the tank, and thepointer of the indicator is pointing to the appropriate part of thechart. If the liquid level rises, arm I2 will move further towards the"oil" position, more current will pass through the indicator and itspointer will move further to the right. Ii, on the other hand. the levellalls, the floats will successively (all. each moving its arm I! to "on"position, so that the indicator hand will move towards zero, Just as itthe (our rheostats were a single instrument controlled by a singlefloat. As the tank fllls again the reverse movements will take place.

It is to be understood that the invention is not limited to the specificembodiment herein illustrated and described, but may be used in otherways without departure from its spirit as deflned by the followingclaims.

I claim:

1. In a liquid level indicating apparatus, a housing adapted forattachment to a tank containing liquid, a rheostat within said housing.a flexible sleeve for sealing the interior of said housing from thecontents of the tank, a movable member within said sleeve pivoted onsaid housing outside of said sleeve and sealed against the contents ofsaid tank, means responsive to change of level of the liquid iorswinging said movable member about its pivot. and means interconnectingsaid member and said rheostat whereby said rheostat is controlled bysaid member.

2. In apparatus 0! the class described in combination, a float adaptedfor movement by change of level of liquid in a tank, a pivoted member,means interconnecting said float and said pivoted member whereby saidmember is movable by said float, a rheostat controllable by said member.and a flexible device rigidly secured to said member and hermeticallysealing said rheostat from the contents of the tank, the pivot for saidmember located outside of said flexible device and sealed against thecontents of said tank.

3.1n a liquid level indicating apparatus. a housing adapted forattachment to a tank containing liquid, a rheostat within said housing.a flexible sleeve for sealing the interior of said housing from thecontents of the tank, a movable member within said sleeve and rigidlyattached thereto, a yoke pivoted within said housing and rigidlyattached to the upper end of said movable member to permit swingingmovement of said member, whereby the pivot for said yoke is sealedagainst the contents of said tank, means responsive to change or levelor the liquid for swinging said movable member upon its pivot, and meansinterconnecting said member and said rheostat whereby said rheostat iscontrolled by said member.

CLARENCE A. n: GIERS.

